1. Field of the Invention
The present invention relates to color photographic materials, more particularly, it relates to color photographic materials containing compounds that release a diffusible dye by a redox reaction associated with the development of silver halide.
2. Description of the Prior Art
A color diffusion transfer dye image forming process using dye releasing redox compounds is disclosed in Japanese Patent Application (OPI) 33,826/1973. The dye releasing redox compounds described in that patent application are p-sulfonamidophenol compounds or p-sulfonamidonaphthol compounds, the dye moiety of which has bonded thereto a non-diffusible phenol moiety or naphthol moiety at the p-position thereof through a sulfonamide group. When a diffusion transfer color photographic unit containing such a dye releasing redox compound in the photosensitive element is image-wise exposed and developed in the presence of a photosensitive silver halide emulsion, the redox compound is oxidized in proportion to the amount of the developed silver halide, the oxidized redox compound is decomposed into a dye moiety having a sulfonamide group and a non-diffusible benzoquinone or non-diffusible naphthoquinone by the action of an alkaline processing solution, and the dye moiety is transferred into an image receiving element of the unit to provide a transfer dye image.
However, according to our experiments and investigations, it was confirmed that the aforesaid p-sulfonamidophenol redox compound did not give a sufficient transfer dye image density, and, in the case of using the p-sulfonamidonaphthol redox compound, non-diffusible naphthoquinone remained in the photosensitive layer after dye release to form a yellow stain therein, and, hence, in the latter case while the transfer image might be utilized the photosensitive element having such a photosensitive layer could not be used as a negative or positive image even if the photosensitive element was subjected to silver bleaching.